On the other hand, clinical recommendations such as the use of both a parenteral benzodiazepine and haloperidol to produce more rapid sedation than monotherapy in the acutely agitated patient [27] or the proper timing to start an angiotensin-converting enzyme inhibitor in the initial management of heart failure [28] are well defined clinical scenarios that should be targets of controlled clinical trials worthy of Class I evidence designation. This evidence concerns the gene ACE and heart failure.